When a chemical system is at equilibrium, Multiple Choice the forward and reverse reactions have stopped. the concentrations of the reactants are equal to the concentrations of the products. the concentrations of the reactants and products have reached constant values. the reaction quotient, Q, has reached a maximum.

Man i dont know this answer

While unproven, it uses facts to support part of a conclusion. it is still factual and has predictive power, however.

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.